Is Russell Wilson better than Zappe right now? Yes
is Russell Wilson likely to be better than Zappe or any of the menagerie of misfits likely to be available in free agency next year? Likely (exception Cousins)
would Russell Wilson be cheaper (cap hit) than just about any other veteran? Yes due to his offsets in his Denver contract
is Russell Wilson the right guy to be “the” guy next year? Less obviously yes. If we’re in a world where the Pats miss out on the big 3 QB prospects (or miss out on 2 and don’t like #3), Wilson - purely on a talent basis - is probably the best the Pats can do. Signing him over Cousins gives them more cap space (again due to the offsets) to add other talent around him and try to maintain a good defense (bringing back Dugger, Jennings, adding depth)
that said, the guy takes a stupid amount of sacks and he’s been in something of a decline. He’s almost always had good deep ball guys and playmakers at WR (Lockett/Metcalf, now Sutton) which the Pats don’t currently have. His play style doesn’t really fit the current offense. He’s at the age where a decline from decent/pretty good to mediocre/bad could come quickly. His personality is reportedly isolating/weird/a problem (not sure how much that’s really worth though).
if the Broncos cut him early, and you can get him short years with maximum amounts of offset, and you have a plan to get a legit deep ball guy or two, and you have a plan for a scheme which fits him, and you’re comfortable with him as a leader/person, and you’re drafting 4th or lower, then it makes a lot more sense than Zappe, Brissett, Ridder, Lock, Rudolph, Winston, Flacco or whoever might be another option via trade or FA
That said, there needs to be a plan to build an offense tailored to him and not just a general plan to add talent. You cant plug him into BOB’s offense with Douglas, Parker (stylistically he kinda fits Wilson but he’s just not a good 1 or 2 or 3a receiver), and whatever they find in middle tier FA.
Im not a huge fan of Wilson, but I’m much less of a fan of watching trash tier QB play and Wilson is likely to be at worst mediocre next year which is a lot more than you can say for Zappe, Garoppolo, Trubisky, pick your favorite backup QB.
If they did get Wilson, id try to pry Courtland Sutton free from Denver. They seem to have decent chemistry and Sutton, when healthy, is a nice not-bank-breaking upgrade. Not sure Denver would move him without an overpay though.